Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch sensitive input devices generally recognize input events when a user touches a touch sensitive surface. Touch sensitive input devices using capacitive touch technology can detect an input event with virtually no force, while other touch sensing technologies (e.g., resistive touch technology) require a somewhat greater amount of force. In contrast, mechanical input devices, such as push buttons for example, generally do not recognize input events unless a user taps or presses the mechanical input device with an amount of force great enough to actuate a switch through mechanical motion. This amount of force is generally greater than the amount of force that would trigger recognition of an input event on a capacitive or resistive touch sensitive surface.
These varieties of input devices exist for performing operations in computing devices, such as desktops, laptops, media players, remote controls, personal digital assistants (PDAs), cellular phones, etc. A user can cause an operation to be performed in computing device by applying an input event to an input device. In one example, a user can move a cursor displayed on a display screen of the computing device by touching an input device in a particular manner. In another example, a user can select an item displayed on the display screen by tapping an input device in a particular location.
With input devices that provide touch sensitive surfaces, various sensor elements can be provided relative to a surface of a computing device, and an input event can be detected by sensing a change in some measure, such as capacitance for example, that is associated with the sensor elements and that exceeds a particular threshold level. If the threshold level is set too low, the touch sensitive surface can become too sensitive, allowing unintended actions (e.g., setting the touch sensitive surface on a table) or effects (e.g., noise) to be detected as an input. If the threshold level is set too high, the touch sensitive surface can become too insensitive, allowing intended input actions (e.g., a light touching of the surface) to go undetected.
Accordingly, determining a proper threshold level for a touch sensitive device can provide unique challenges.